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TITLE	Central-to-Axial-to-Central Chirality Transfer in the Au(I)-Catalyzed Cycloisomerization of Propargyl Vinyl Ethers to Cyclopentadienes
AUTHOR	Dina Scarpi, Giovanni Turchi, Matteo Fazzini, Lucilla Favero, Ernesto G. Occhiato*
YEAR	2025
JOURNAL	The Journal of Organic Chemistry
ABSTRACT	An easy approach to the enantioselective synthesis of five-, six-, and seven-membered ring-fused cyclopentadienes (85–99% ee) is based on the Au(I)-catalyzed cycloisomerization of enantiomerically pure or enriched propargyl vinyl ethers, which occurs with complete central-to-axial-to-central chirality transfer. DFT calculations show that the formation of a nonplanar σ-Au(I)-pentadienyl cation intermediate having a helical configuration, which quickly cyclizes to form the target cyclopentadiene, accounts for the lack of erosion of the initial optical purity. From a synthetic point of view, when the cyclopentadienes are subjected to a quick 1,5-H shift and cannot be isolated as pure regioisomers, they can be trapped in situ by suitable dienophiles during or immediately after the gold(I)-catalyzed cycloisomerization to form more complex polycyclic compounds. The synthesis of an enantiomerically pure α-tertiary amine was realized to demonstrate the usefulness of this approach.
FULL ARTICLE	https://pubs.acs.org/doi/full/10.1021/acs.joc.5c00433
INSTRUMENT	DIP-370
KEYWORDS	Chirality, Chromatography, Isomerization, Propargyls, Vinyl

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